Inorg. Chem. 19815, 24, 3505-3501 t/et
I
EuLiC14. Such methods seem particularly important as routes to metastable compounds or those of borderline stability. Another ternary halide that is obtained by a similar route is KYb2C17.9 It is expected that the solid-state reactions of other ammonium compounds with various metals and their compounds follow similar pathways and that their investigation will provide important insights in the production of industrially and technologically useful products. Acknowledgment. Support by Deutsche Forschungsgemeinschaft, Bonn, West Germany, and Verband der Chemischen Industrie, Frankfurt, West Germany, is gratefully acknowledged.
MBr3
60,1
100
232
230
228
-
226
224
222
220
218
216
VmKs,NaMBr,l /cm3 mol-'
Figure 1. Survey of the ammonium bromide route to anhydrous rareearth-metal bromides, MBr3, showing the complex ammonium bromides stable at room temperature for M = La-Ho and their decomposition pathways as determined by Guinier-Simon X-ray patterns. Instead of the ionic radii of the trivalent rare-earth-metal cations, the molar volumes of the elpasolites Cs2NaMBr6 (see: Meyer, G.; Gaebell, H.-Chr. Z . Narurforsch., B Anorg. Chem., Org. Chem. 1978,33B, 1476) are used as abscissa.
chlorides must be interpreted as a two-step procedure with acid-base reaction and complex formation first and decomposition ~ e c o n d . This ~ method also functions beautifully for the analogous bromides and iodides. The ammonium bromide route was particularly explored. Reaction of NH4Br and rare-earth-metal oxide, M2O3, yields (NH4)2MBr5for M = La-Nd, and (NH4)3MBr6 for M = Sm-Lu. Decomposition of the latter passes through (NH4)2MBr5for M = Sm and Eu, and NH4M2Br7is observed as an intermediate for M = Nd-Dy. Figure 1 summarizes the results. The crystal structures of the halides (NH4)2MXS(X = C1, Br, I) are that of K2PrC15,6,7and the halides NH4M2X7are isotypic with KDy2C17or RbDy2C17.*y9 The versatility of the ammonium halide reactions is furthermore reflected by the fact that the complex halides themselves, especially (NH4)2MX5and (NH4)3MX6,are useful starting materials. For example, (NH4)3YC16reacts at temperatures as low as 300-400 "C with both gases ( H 2 0 , H2S) or solids (Y2O3, Y2S3) to yield YOCl and YSCI, respectively. This is particularly interesting because Y 2 0 3does not react at these temperatures with HCl gas at all. The usual route to YOCl is the reaction of YC13with H20, air, or Y 2 0 3around 500 O C . It is then obtained in the PbFCl type structure. The reaction of (NH4)3YC16with Y203,however, provides an easy a c e s to YOF-typelo YOC1. Its close relationship to the novel monochloride YCl with its rich interstitial chemistry has been particularly emphasized.'' Thermal analyses of Y 2 0 3 and NH4Cl mixtures (1:2 molar ratio) that have recently been interpreted in terms of intermediates such as [M(NH3)3]C1312-'3 are certainly misinterpreted. Additionally, the complex ammonium halides react not only with chalcides (Y203,Y2S3,YSe), but also with pnictides such as YP (yielding Y2PC13). Furthermore, alkali-metal halides like LiCl react with, for example, (NH4)2EuC15to yield via the intermediate (NH4)&iEuC16 the new scheelite-typeI4 compound (3) (4) (5) (6) (7)
(8) (9) (10) (1 1) (12) (13)
3505
Reed,J. B.; Hopkins, B. S.;Audrieth, L. F. Inorg. Synth. 1939, 1,28. Taylor, M. D. Chem. Rev. 1962, 62, 503. Meyer, G.;Ax, P. Marer. Res. Bull. 1982, 17, 1447. Meyer, G.; HOttl, E. Z . Anorg. Allg. Chem. 1983, 497, 191. Meyer, G.; Soose, J.; Moritz, A.; Vitt, V.; Holljes, Th. Z . Anorg. Allg. Chem. 1985, 521, 161. Meyer, G. Z . Anorg. Allg. Chem. 1982, 491, 217. Meyer, G.; Ax, P.; Cromm, A.; Linzmeier, H. J . Less-Common Met. 1984, 98, 323. Mann, A. W.; Bevan, D. J. N. Acra Crystallogr., Secr. E : Strucr. Crystallogr. Cryst. Chem. 1970, 826, 2129. Garcia, E.; Corbett, J. D.; Ford, J. E.; Vary, W. J. Inorg. Chem. 1985, 24, 494. Holsi, J.; Niinisto, L. Thermochim. Acta 1980, 37, 155. Starick, D.; Herzog, G.; Naumann, R. Wiss. Z . Erst-Morifr-AmdtUniu. Greifsw., Marh.-Natunviss. Reihe 1982, 31, 45.
Registry No. NH4C1, 12125-02-9; NH4Br, 12124-97-9; NH41, 12027-06-4; Li, 7439-93-2; Zn, 7440-66-6; La, 7439-91-0; Y, 7440-65-5; Cu, 7440-50-8; UH3, 13598-56-6; NH4Re04,13598-65-7; Li3N, 261 3462-3; LiY02, 12169-03-8; YzO,, 1314-36-9; Y2S3, 12039-19-9; YP, 12294-01-8; (NHb)3YCI6, 59230-45-4; (NH4),YBr6, 98218-63-4; (NH4)3Y16, 98218-64-5; (NH4)2EuC15, 97253-02-6; (NH4)2LiEuC16, 98218-65-6; (NH4)2UCI6, 22949-76-4; NH4YZCI7, 84556-33-2; (NH&SmBr6, 98218-66-7; (NH4)2SmBr5, 98244-73-6; NH4Sm2Br7, 98218-67-8; H 2 0 , 7732-18-5; H2S, 7783-06-4; LiCI, 7447-41-8; NH3, 7664-41-7; (NH4),ZnCI4, 14639-97-5; (NH4)2LaC15,78476-14-9; (NH4)2CuC13,61288-98-0; Re, 7440-15-5; N,, 7727-37-9; HC1, 7647-01-0; H,, 1333-74-0; (NH4)2LiYCl6, 98218-68-9; PH,, 7803-51-2; YOBr, 15923-89-4; YOI, 66923-06-6; YOCI, 13759-29-0; YSCI, 98218-69-0; LiEuC14, 98218-70-3; U C 4 , 10026-10-5; YCI3, 10361-92-9; SmBr,, 13759-87-0. (14) Meyer, G. Z . Anorg. Allg. Chem. 1984, 511, 193.
Institut fur Anorganische und Analytische Chemie Justus-Liebig-Universittit 6300 Giessen, West Germany
Gerd Meyer*
Thomas Staffel Siegfried Diitsch Thomas Schleid
Received May 30, 1985
Configurational Processes in Coordinated Ligands. Extremely Facile Phosphorus Inversion in the Pyramidal Terminal Phosphide Complexes ($-CSHs)Re(NO) (PPh3)(PRR')
Sir: Although configurational processes at coordinated sulfur and selenium have been studied extensively,' little is known regarding inversion barriers at coordinated p h o s p h o r u ~ . ~Complexes ~~ with terminal pyramidal phosphide ligands have been of considerable recent i n t e r e ~ tand , ~ in a brief note Malisch has indicated that ($-CsH5)W(CO)2(PMe3)(P(i-Pr)2) has a phosphide phosphorus inversion barrier of 14.4 kcal/mol.* We have become interested in the structure and reactivity of chiral pyramidal phosphide complexes (qS-C,H,)Re(NO)(PPh3)(PRR'),S and we report here their dynamic N M R behavior and configurational stability at rhenium. These data establish inversion barriers that are among (1) (a) Murray, S. G.; Hartley, F. R. Chem. Rev. 1981,81, 365. (b) Abel, E. W.; Bhargava, S. K.; Orrell, K. G. Prog. Inorg. Chem. 1984, 32, 1. (c) Abel, E. W.; Bhargava, S.K.; Orrell, K. G.; Platt, A. W. G.; Sik, V.; Cameron, T. S.J . Chem. SOC.,Dalron Trans. 1985, 345. (2) Malisch, W.; Maisch, R.; Meyer, A.; Greissinger, D.; Gross, E.; Colquhoun, I. J.; McFarlane, W. Phosphorus Sulfur 1983, 18, 299. (3) Salem, G.; Wild, S . B. Inorg. Chem. 1984, 23, 2655. (4) See, inter alia: (a) Hutchins, L. D.; Duesler, E. N.; Paine, R. T. Organomefallics 1982, 1, 1254. (b) Baker, R. T.; Whitney, J. F.; Wreford, S . S.Ibid. 1983, 2, 1049. (c) Bohle, D. S.;Jones, T. C.; Rickard, C. E. F.; Roper, W. R.J . Chem. Soc., Chem. Commun. 1984, 865. (d) Ebsworth, E. A. V.; Gould, R. 0.; McManus, N. T.; Pilkington, N. J.; Rankin, D. W. H.J . Chem. Soc., Dalton Trans. 1984, 2561. (e) Weber, L.; Reizig, K.; Bocse,R. Chem. Ber. 1985,118,1193. ( f ) Angerer, W.; Sheldrick, W. S.;Malisch, W. Ibid. 1985, 118, 1261. (8) Ebsworth, E. A. V.; Mayo, R. Angew. Chem., Int. Ed. Engl. 1985, 24. 68. ( 5 ) Bu'hro, W. E.; Gcorgiou, S.;Hutchinson, J. P.; Gladysz, J. A. J . Am. Chem. Soc. 1985, 107, 3346.
0020-166918511324-3505$01.50/0 0 1985 American Chemical Society
Communications
3506 Inorganic Chemistry, Vol. 24, No. 22, 1985
- b'PhH
PPh3
1
I3C{ 'H} +52T
-7'C
H
I 1
- 24OC A
J
L
l
L
-33 25 17
I1
-91 -99-107-115
PPm
Figure 1. Variable-temperature 31P{1H) N M R spectra of 1 in THF.
the lowest yet observed for trivalent phosphorus.6 The phosphide complexes (q5-CsHs)Re(NO)(PPh3)(PRR') were prepared in 80-92% yields by the sequential reaction of (q5-CsHJ)Re(NO)(PPh3)(OSO2-p-C6H4CH3) with PRR'H and then O-~-BU-K+.~,~ The phenylphosphide complex (qS-CsH5)Re(NO)(PPh,)(PPhH) (1) was studied first. Low-temperature 31P(1H) N M R spectra of 1 showed two PPh3 and two PPhH resonances (Figure l), corresponding to two isomers. These isomers interconverted, for a t higher temperatures both sets of resonances broadened, coalesced, and resharpened as shown in Figure 1. Similarly, the -74 "C 'H NMR spectrum of 1 (THF-d8) contained two v5-C5Hs(6 5.19, 4.85) and two PH (6 3.74 (br dd, 'JPH = 209 Hz), 3.34 (br d, lJPH = 199 Hz)) raonances of equal intensity, which coalesced to a single set of resonances at higher temperatures. From the q5-C5H5resonances, AG*z43= 11.5 f 0.1 kcal/mol was calculated.8 The KBr IR spectrum of complex 1 also exhibited two well-separated vNIO (1654, 1627 cm-I (vs)) and (228 1 , 2255 cm-' (m)) absorbances. We considered it highly probable that the two isomers were the diastereomers (RS,SR)-1and (RR,SS)-1. However, from the above data the possibility that the isomers were two Re-PPhH rotamers of a single diastereomer of 1 could not be rigorously excluded. Accordingly, we prepared the phosphide complex (q5-C5H5)Re(No)(PPh3)(P(p-C6H,CH3)2) (2, Figure 2),7 in which the diastereotopic p-C6H4CH3groups could not be exchanged by a (6) (a) Mislow, K. Trans. N.Y. Acad. Sci. 1973, [2] 35, 227. (b) Macdonell, G. D.; Berlin, K. D.; Baker, J. R.; Ealick, S. E.; van der Helm, D.; Marsi, K. L. J. Am. Chem. Soc. 1978,100,4535. (c) Schmidbaur, H.; Schier, A.; Lauteschkger, S.; Riede, J.; Muller, G. Organometallics 1984, 3, 1906. (7) Microanalytical, IR, and NMR ('H, I3C,,IP)data for each new compound are.given in the supplementary material. (8) Sandstrom, J. "Dynamic NMR Spectroscopy"; Academic Press: New York, 1982.
- 22
21
20
PPm Figure 2. Variable-temperature "C('H) and CH3 groups of 2 in THF-d8.
2,4
12.2
'H N M R spectra of the
rotational process. Although the 31P(1H) N M R spectrum of 2 (THF-d8, -32 "C: 19.23 (d, J p p = 1 5 . 3 HZ), -50.98 (d, J p p = 15.3 Hz) ppm) was essentially temperature independent (-62 to +50 "C), the 'H and I3C(IH)N M R spectra showed a dynamic process that equivalenced the p-C6H4CH, groups. From the CH, resonances of the 'H N M R spectra (Figure 2), AGIZb4= 13.0 f 0.1 kcal/mol was calculated.8 Hence, isomerization of 2 (and, by extrapolation, 1) requires an inversion of configuration. In principle, the inversion of configuration could involve either the phosphorus or rhenium atoms. Hence, optically active 2 ([ct]25546 = 397", c 0.00073 g/mL, THF, 25 "C) was prepared and from (-)-(S)-(~5-C5Hs)Re(NO)(PPh,)(OS0,-p-C6H4CH3)~ it was found to be configurationally stable (3 h,
